1. Field of the Invention
The present invention relates to a veterinary composition and method and more particularly pertains to veterinary compositions and methods of use for preventing and treating fleas and ticks.
2. Description of the Prior Art
The use of veterinary techniques is known in the prior art. More specifically, veterinary techniques previously devised and utilized for the purpose of preventing and treating fleas and ticks are known to consist basically of familiar, expected, and obvious structural configurations, notwithstanding the myriad of designs encompassed by the crowded prior art which has been developed for the fulfillment of countless objectives and requirements.
The control of fleas and other external parasites of domestic animals has become an important part of domestic life. The substantial increase in pet ownership has meant that the market for such products has increased dramatically.
To undertake control of such parasites pet owners have a variety of options:                Bathing the pet in a medicated wash        Spraying the pet with a medicated solution        Placing a pesticide-impregnated collar around the neck of the pet        Giving the pet a tablet containing an effective ectoparasiticide compound able to reach an efficacious level in the blood        
More recently it has become popular to treat pets for fleas and ticks by applying a medicated liquid formulation to one or more spots on the back of the pet. To achieve this all-over efficacy such formulations rely either on the transdermal absorption, or topical translocation of the ectoparasiticide to other parts of the body. A number of different ectoparasiticides have proven to be effective when delivered in this manner. Of particular note is the phenylpyrazole derivative (5-amino-1-[2,6-dichloro-4-(trifluoromethyl)phenyl]-4-(trifluoromethylsulfinyl)-1H-pyrazole-3-carbonitrile), fipronil, marketed under the trade name FRONTLINE Spot-On.
Patent applications EPO 295 117 and EP 0 352 944 describe fipronil, as well as, a large family of N-phenylpyrazoles, which have a very broad spectrum of activity, including antiparasitic activities.
Although they are effective when delivered in the manner described above, N-phenylpyrazole derivatives are sometimes difficult to formulate since they are not readily soluble in the common excipients used for topical pesticide treatments. Moreover, when formulated in such excipients, the formulations can have a significant potential for crystallisation.
To address this issue, there has been a number of alternative formulation systems proposed that combine a crystallisation inhibitor with one or more solvent/co-solvents. For example;
U.S. Pat. No. 6,395,765 (Merial) addresses the problem of crystallisation of the N-phenylpyrazole active through the use of a combination of a crystallization inhibitor; an organic solvent having a dielectric constant of between 10 and 35, preferably of between 20 and 30; an organic co-solvent having a boiling point below 100° C., preferably below 80° C., and a dielectric constant of between 10 and 40, preferably of between 20 and 30. In the formulation marketed under this patent (FRONTLINE/FRONTLINE Plus) the crystallisation inhibitor used is polyvinylpyrollidone combined with a surfactant; the solvent used is Diethylene glycol monoethyl ether solvent; and the co-solvent is ethanol.
Other more recent patent examples include:
WO 2010092355 (Cipla) which proposes use of a crystallisation inhibitor such as Polyvinyl pyrollidone in conjunction with a solvent system selected from polyoxyethylenated ester of sorbitan, a polyoxyethylene castor oil derivative, propylene glycol; a fatty acid ester of propylene glycol such as propylene glycol monocaprylate, propylene glycol monolaurate; an oleoyl macrogol glyceride; a caprylocaproyl macrogol glyceride; a polyethylene glycol; a copolymer of ethylene oxide & propylene oxide; or a combination thereof. Furthermore, this patent has flash point constraints along with constraints on the use of a surfactant.
US 20110060023 (Donnelly) proposes the use of at least one crystallisation inhibitor such as polyethylene glycol or polyethylene glycol hydrogenated castor oil combined with a solvent system made up of up to 8% of one C1-C6 alcohol co-solvent combined with at least one organic solvent which is not the C1-C6 alcohol co-solvent. The crystallization inhibitor is present in from 2% to 20% by weight of the formulation.
CN 101804048 (Shanghai Hanwei Biopharmaceutical) proposes the use of a crystallisation inhibitor selected from dimethylsulfoxide, cellulose acetate butyrate, N-methylpyrrolidone, N,N-dimethylacetamide, glycerol acetone, isosorbide dimethyl ether and propylene carbonate, combined with at least one solvent and at least one co-solvent. The preferred formulation also suggests the inclusion of DMSO as a co-solvent.
GB 2464449 (Norbrook) suggests use of a glycol ether combined with butanol and/or DMSO.
Many of these recent patents lack exact detail on the purpose of each specific excipient and also do not provide examples of how a formulation could be prepared using each of the excipient combinations claimed and appear to be lacking the necessary enablement.
In this respect, the veterinary compositions and methods according to the present invention substantially departs from the conventional concepts and designs of the prior art, and in doing so provides an apparatus primarily developed for the purpose of preventing and treating fleas and ticks.
Therefore, it can be appreciated that there exists a continuing need for a new and improved veterinary compositions and methods which can be used for preventing and treating fleas and ticks. In this regard, the present invention substantially fulfills this need.